Navy research into phase change may pave way for better battlefield chemical sensors

WASHINGTON. An interdisciplinary team of scientists at the U.S. Naval Research Laboratory (NRL) have demonstrated that monolayer 2-D Transition Metal Dichalcogenides (TMDs) — which are atomically thin semiconductors — undergo a change from semiconductor-to-metallic phase when exposed to airborne chemical vapors.

This newly discovered behavior opens up an entirely new possibility for a new type of low-power, flexible, sensors that can identify chemical compounds and the presence of dangerous vapor.

The team validated optical and electronic evidence of the phase transition and tracked how the TMDs can be used to create an entirely new class of chemical vapor sensors, a class of detectors that is selective to specific nerve agents and explosive compounds, which are of great concern on modern battlefields.

Dr. Adam L. Friedman, research physicist, Material Science and Technology Division, said of the findings: “These materials are extremely promising for chemical vapor sensing applications because the inherent few-atom-thickness of the material greatly enhances their sensitivity to even the smallest surface disturbance. Apart from the immediate interest to basic research, as this particular method of creating of phase transition in TMDs has never been observed or explored before, it has great potential application in a new type of phase-based, multifunctional chemical vapor sensor.”

An interdisciplinary team of scientists at the U.S. Naval Research Laboratory (NRL) has demonstrated optical and electronic evidence of semiconductor-to-metallic phase transition when exposed to airborne chemical vapors, and how the behavior can be used to create an entirely new class of chemical vapor sensors. Back row from left to right: Research physicists Drs. Aubrey Hanbicki, Paul Campbell, Adam Friedman, and Jim Culbertson. Seated front: Dr. Glenn Jernigan, research chemist; and Dr. Keith Perkins, electronics research engineer. (Photo: U.S. Naval Research Laboratory/Gayle Fullerton)